Airplane wing



F. R. MAXWELL AIRPLANE WING Aug. 7, 1945.

File@ Feb. ll, 1942 `5 Sheets-Sheet 1 s# a F76'.

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5 Sheets-Sheet 5 Aug. 7, .1945. F. R. MAXWELL kAIRPLANE WING Filed Feb. l1, 1942 Allg' 7 1945- F. R. MAXWELL 2,381,678

AIRPLANE WING Filed Feb. ll, 1942 www 5 Sheets-Sheet 4 F. R. MAXWELL Filed Feb. ll, 1942 5 Sheets-Sheet 5 Patented-Aug. 7, 1945 AIBPLANE WING Frank R. Maxwell, Rose Valley, Pa. c pplication February 11, 1942, Serial No. 430,317

8 Claims.

" This invention relates to an improvement in wings for airplanes and, more particularly, to an improvement in such wings of the type provided with, means for lforming a slot adjacent to the leading `edge adapted to be opened in cooperation with operation of a rear flap.

Heretofore it has been known in airplane practice to provide a wing with means for forming a continuous slot extending adjacent the leading edge from the root of the wing to adiacentthe tip, inv order to increase the lift on the wing and enable lower flying speeds and consequentlylower landing speed.

As will be appreciated, the purpose .of the wing slot is to increase the angle of incidence at which the wing. stalls and thereby increase the maximum lift of the wing. However, in many wings the angle at which the various sections oi' theA wing stall varies from root to tip of the wing. Thus, for example, in the case' of a tapered wing the section adjacent to the top usually stalls before the section adjacent to the root, and vice versa in the case of astraight wing.

Desirably, in order to obtain the maximum lift, a wing slot will be so designed that all portions of the wing will stall at approximately the same angle of incidence and that angle will be the largest attainable. Further, it is essential that that section of the wing near the tip, in the way of the aileron, or other means of lateral control, should not stall before the center section and,

preferably, a little after the center section, so

that lateral control may be maintained at and adjacent to the point of stall of the entire wing. As will vbe apparent, the slots as heretofore used and of the continuous type are not eiective to adjust the angle of incidence ofa wing to the maximum obtainable amount and. at the same time, retain adequate lateral control. when the wing is of a type such that the natural angle of stall without slots variesv in different sections throughout the lateral extension of the wing.

Now in accordance with this invention, I provide a wing having means for forming a slot which is effective to adjust the angle of incidence of a wing to the maximum amount with retention of lateral control up to the stall. The novel slot according to this invention comprises a plurality ofsections, adjacent the leadingedge and extending from the root to'adjacent the tip of the wing. 4

More particularly, the several sections of the slot may be of different contour, of dierent length and of different width, or tapered, all respectively with relation to the portions of the wing and the chord thereof with which they are respectively related and the aerodynamic conditions `obtaining with respect thereto. Further, the several sections may be at different angles relative to the chord of thewing.

Further, more particularly, means may be provided whereby the several sections forming the slot may be opened different amounts to the end that the angle of. maximum lift may be varied throughout the extension of the wing with reference to the airodynamic effects obtaining in different portions of the wing when the eiect of the slot is utilized.

Having now indicated in a general way the' nature and purpose of this invention, I will proceed to a detailed description of a' preferred em-` bodiment with reference to the ac drawings, in. Which: Figure 1 is a plan view, partly broken away.

a wing having a rear flap and provided with companying means for forming a slot comprising a pluralityv of sections according to this invention.

Figure 2 is a sectional view on line 2 2, Figure l, looking in the direction of the arrows.

Figure 3 is a sectional view on line 3 3, Figure l, looking in the direction of the arrows.

Figure ,4 is a sectional view on line 4 4, Figure 1, looking in the direction of the arrows.

Figure 5 is a plan view, partly broken away, of a wing embodying. a modication of this inven-` tion as shown in Figure 1. Figure 6 is a fragmentary sectional view showing' means for forming one of the slot sections in closed position with'means for opening and closing the slot.

Figure 'I -is a sectional view showing the' subject of Figure 6 with the slot open.

operation.

Figures 9 and 10'are diagrammatic views exemplifying the cooperative movement of slot forming means andthe flap.

Figures v11 and 12 are fragmentary sectional views showing modification of the means for opening and closing the slot, the slot being vshown closed in Figure 11 and open in Figure l2.

Figure 13 is a sectional fragmentary view of a rear flap with modied means for manipulating it. Figures 14-16 are fragmentary sectional views y of other modied means for opening and closing the slot, the slot being shown closed in Figure 14 and open inFlgures 15 and 16.

Referring to the drawings, the fuselage of an airplane isindicated at I, while 2 indicates a with relation to the chord of the wing, it being noted that the several sections as shown are of uniform width, but that, however, the chord of the wing varies in the extension of the wing fromv root to tip. However, as shown ln Figure 5, a constant relation between slot width and wing chord may be maintained by, as shown, tapering the slot with the taper of the wing. Again, as shown in Figure 1, the slot sections may vary in length, it being noted that the middle section is shorter than the end sections.

With reference to Figures 2-4, it will be noted that the contour of the slot in cross section is varied in the several sections, the particular contour for the several sections being selected to give the maximum lift throughout the extension of the slot with reference to the stalling point of the wing at diierent points along its extension.

As has been indicated, the slot, comprising the sections 3A, 3B and 3C, is adapted to be opened in cooperation with operation of the trailing edge flap 4, it being noted that the several sections of the slot may be opened an equal amount or respectively in different amount, and in cooperation with operation of the trailing edge flap.

To such end an arm 8 (Figure 8) is attached at one end to the trailing edge'flap 4, for example, to the hinge pintle I of the-flap, which in usual manner is hinged to the wing and in inoperative position fits into a recess 6 in the underside of the wing, and at its other end to the rod 9, by a pivot I0. The rod 9 extends longitudinally of the chord of the wing and is connected to any suitable form of mechanism, as a screw and nut mechanism, indicated at 9' (Figure 1) with connection to operating means located conveniently to the pilot and adapted to exert a push or pull on the rod for lowering and raising the flap into and out of operative position. As will be apparent from an inspection of Fie/ure 1, a plurality of arms and rods similar to arm 8 and rod 9 will be provided for the operation of the ilap.

A segment II, having a plurality of openings I2 adjacent to its periphery, is attached, for example, to the pintle l1 or otherwise to work with arm 8. The segment II is connected by an adjustable link I8 to a lever I3, pivotally mounted, as at I5, on a bracket I6 secured to an element of the internal structure of the wing. One arm of the lever I3 is connected to a rod I9, as at 20, while its other arm is extended and provided with a plurality of openings I1. It will be noted from an inspection of Figure 8 that the link I8 may be connected to the segment II through any one of the apertures I2 and to the lever I3 through any one of the apertures I1.

The arm I9 extends longitudinally of the chord of the wing and is pivotally connected, as at 22 (Figures 6-7) to an arm of a bell crank lever 2I,

which in turn is pivotally mounted, as at 23, on

an element of the internal structure of thewing, at a point adjacent to the slot 3. .To another arm of the lever 2I is attached, as at 25, a link 24 which in turn is connected to an adjustable link or turnbuckle 2l, which in its turn is pivotslly connected, as at 21, to the underside of the upper slot cover 2l. The angularity of the link 24 may be adjusted with respect to the lever 2l by means of a threaded rod 42 pivotally connected at yone end, as at 42, to the link 24 and extending through a nut 45 pivotally mounted, as at 44, on lever 2 I.

The third arm of the lever 2I is connected to a link 33, through a slot and pin connection 39, 40. Figures 6-7, the link 38 beingin turn connected, as at 31, to a lever 32 pivotally mounted, as at 35. on the upper slot cover 2l. The lever 33 is in turn connected, as at 34, to an adjustable link 3l pivotally mounted, as at 32, on the lower slot cover 30. A spring 4I is connected to the lii ilr'3l';"`---` and to an element of the internal structure of the wing.

As will be appreciated from an inspection of Figures 1 and 5, a plurality of rods similar to rod I9 and connections therefrom to the upper and lower slot covers 2l and 30, as through levers similar to lever 2 I, are provided for the covers forming the sections of the slot, as, for example, sections 3A and 3B, opposite to the rear ilap.

For operation of the covers 23 and 30 of the section 3C of the slot beyond the outer end of the rear ap, as shown in Figure l, the outer rod I9 is connected to a rod 4l extending longitudinally of the wing by vmeans of a lever 48 mounted in the wing and the rod 41 is connected to a pair of levers 2| through the medium of levers 48 mounted in the wing and short arms'IS'.

For the operation of the covers 28 and 3 0 for the opening of the sections of the slot 3 in cooperation with operation of the rear flap 4, the

adjustable links I8 are connected to the seg-y ments Il and levers I3 for desired relative movement of the ap and slot covers. Thus, by reference to Figure 9, it will be noted that if the links are connected through the medium of the opening I in both the segment and lever, th'e lever I3 will not move to open the slot until the segment has turned substantially with consequent downward movement of the flap. Again (Fig. 10), if the connection between opening I in the lever and opening IV n the segment is made, the lever will be moved when the segment is moved with consequent opening of the slot when the ap starts to move downward. It follows that various opening of the slot as a whole or of its various sections respectively with respect to downward movement of the flap may be obtained by variously connecting the links I8 to the segments II and levers I3, as a whole or as they control the openings of the several slot covers respectively.

Again, the degree of opening of the slot covers, respectively, is adjustable through adjustment of the angularity of the links 24 with respect to the bell crank levers 2l, through the medium of the threaded rods 42 and nuts 45.

The flap and slot cover operating mechanism having been adjusted for the desired timed opening of the sections of the slot with respect to the operation of the ilap and for the degree of opening of the several sections of the slot, respectively, it is believed that the operation of the mechanism will be obvious, it being noted that, on operation by the pilot oi' the screw and nut 9 for lowering the flap 4 to an operative position, the segments II will be turned, causing the levers I3 to be rocked and to push the rods I9 forward. The forward movement of the rods I8.

will cause the levers 2 I to be rocked with the resuit that the upper and lower slot covers will be raised to open the slot sections 8A and IB.. The slot section 3C will be opened at the same time through the medium of leverl 4I, rod Il, levers 4B and rods i9'. It will be noted that the connections between levers 2l and the lower slot cover and, more particularly, the slot and pin connection between links 3d and levers 2|, together with the action oi springs (I on links 3l, will permit the lower slot covers 30 to' be fully opened in the initial opening movement of the upper slot covers it, i. e., before the slots are effectively opened, and to permit them to remain in fully open position during the range of movement of the upper covers 2B for effective opening of the slot sections.

As has been indicated, the several slot sections may be opened in various timed relation to operation of the rear ilap and respectively to did'erent extent by adjustment of the links it with respect to the segments H and levers I3 and by adjustment of the angular relationship of the links 2li with respect to the levers 2l through the medium of threaded rods 62 and nuts 45.

Referring now to Figures l1 and l2, in which are shown modiiled means for opening and closing the slot, the push rod i9 is pivotally con,

nected to a three armed lever di, vpivotally mounted as at 52 within the wing structure adjacent to the slot 3, a longitudinally adjustable link 54 is pivotally connected to another arm of the lever l as at 53 and to the upper slot cover it as at t6.

The lower slot cover t9 is provided with an arm tl, to which is pivotally connected a sleeve @3, within which is a spring 04 and within which extends arod G5 pivotally connected to the lever 5i as at 66. The rod 65 is engaged with the sleeve 63 through the medium of a slot and pin connection 6T, 68. For adjustment of the slot opening inthe modiiication of Figures 11 and 12, it will be noted that the lever 5I is provided with a plurality of apertures 'l0 enabling the link 54 to be variously positioned in its connection with the lever 5I. Thus, by connecting `the adjustable link Il with the lever Il through dlilerent apertures 1l, the i'ull opening of the upper slot cover can be varied, as shown in full and dot dash lines Figure 12.

Further, it will be noted from an inspection of Figure 11 that when the slot cover is closed the pivot points 52, 53 and il are in line and hence forces acting to open the upper slot cover are not transmitted to other control surfaces.

With reference to Figure 13, it will be noted that the rear iiap 4 is `operated through the medium oi an arm 1l mounted on the pintle 1 and pivotally connected to the push rod I9 at 'l2 in distinction from the arrangement shown in Figure 8.

Referring now to Figures 14-16, a lever 8| is pivotally mounted within the wing structure as at l2. The push rod Il is pivotally connected to an arm of the lever as at". An adjustable link Il is pivotally connected to the upper slot cover,

as at B6, and to the lever Il by means oi a pin 83 passed through one or another of the apertures 83. 'I'he apertures 83', it will be noted,

extend in a line radially from the pivotal mounting l2 o! the lever. The link B4 is bent to avoid interference with the pivot I2. 'I'he lower slot cover 89 is provided with an arm ll, to which is pivotally connected. as at IMI, a sleeve l2 within which is a spring 93 and into which extends a rod ,pivotally connected to lever-li, as'. at 95.

The sleeve 82 and the rod 94 are connected through the medium of slot and pin connection By reference to Figure 14, in which the slot covers are shown to be in closed position, it will be noted that with the slot covers closed the pivots da, d2, 8B are substantially in line, as arel alsothe pivots 82, 9E and I 00.

The in line relationship of the pivotal connections indicated will, as will be appreciated, prevent the forces acting upon the upper slot cover and upon the lower slot covery from operating to open these covers, and it will also prevent transmission of such forces to other portions of the mechanism.

As shown in Figure 16, various opening of the 'upper slot cover may be obtained by use of one or another or the openings 83' for connection of the adjustable link 85 to the lever si. As will be appreciated, the lower slot cover, due to the construction of the member connecting the arm iii with the lever ti, will be fully opened when the upper slot cover is opened, irrespective of the adjustment for amount oi opening of the upper slot cover.

The several slot sections may be given the same or different contours andthe several sections rnay vary in width proportionally to the chords oi the wing or be constant with respect thereto.

is will he obvious from the foregoing description, the wing 2 provides a main airfoil section we the upper slot covers 2B form auxiliaryy airfoil sections arranged relative to the leadingedge of the main section 2 to form the slots 3A, iB, aC. The profile sections of the covers, or

auxiliary airfoil sections 28, respectively are ol different contour, it being noted from an inspection of Figures 2, 3 and 4 that the angles of i'ncidence of the several auxiliary airioil sections are different, and that more speciilcally the angies oi incidence of the sections respectively diminish in a direction from the root toward the tip oi' the 'main section, i, e., the angles of in cidence of the auxiliary al1-foil sections forming the slot 3B (Fig. 3) is less than that of the auxiliary airfoil section forming the slot 3A (Fig. 2) and that of the auxiliary airfoil section forming the slot 3C (Fig. 4) is less than that of the auxiliary airtoil section forming theslot 3B (Fig. 3). As will also be obvious, if a single auxiliary airfoil section, in place of a plurality of auxiliary airfoil sections, is provided to form a single slot, proiile sections oi' the auxiliary airfoil section taken at ditlerent points in its longitudinal ex- .J tension'will be of different contour.

It will` now be appreciated that by virtue oi' this invention a slot extending effectively from the root of a wing to adjacent its tip, is provided which aerodynamically will exactly complement the various aerodynamic conditions obtainingv in the various parts of the wing in itslongitudinal I leading edge of the main section to form a slot,

said auxiliary airfoil being characterized by the fact that the angle of incidence of the proiile sections thereof taken at a plurality of di'erent points in its longitudinal extension diminishes progressively in a direction from the root toward the tip of the main airfoil section.

2. An airfoil comprising a main airfoil section and an auxiliary airfoil movable relative to the leading edge of the main section and adapted to be positioned to form a slot, said auxiliary airfoil being characterized by the fact that profile sections thereof taken at a plurality of different points in its longitudinal extension are of different contour.

3. An airfoil comprising a'main airfoil section and an auxiliary airfoil movable relative to the leading edge of the main section and adapted to be'positioned to form a slot, said auxiliary airfoil being characterized by the fact that profile sections thereof taken at a plurality of diiferent points in its longitudinal extension have dififerenis angles of incidence.

4. An airfoil comprising a main airfoil section and an auxiliary airfoil movable relative to the leading edge of the main section and adapted to be positioned to form a slot, said auxiliary airfoil being characterized by the fact that the angles of incidence of prole sections thereof taken at a plurality of different points in its longitudinal extension diminish progressively in a direction from the root toward the tip of the main airfoil section.

5. An airfoil comprising a main airfoil section and a plurality of auxiliary airfoils movable relative to the leading edge of the main section and adapted to be positioned to form a plurality of slots extending successively in a direction from the root to the tip of the main airfoil section, said auxiliary airfoil sections being characterized by the fact that their protlle sections respectively are of different contour.

6. An airfoil comprising a main airfoil section and a plurality of auxiliary airfoils movable relative to the leading edge of the main section and adapted to be. positioned to form a plurality of slots extending successively in a direction from the root to the tip of the main airfoil section, said auxiliary airfoil sections being characterized by the fact that their proille sections respectively are'of different length.

7. An airfoil comprising a main airfoil section and a plurality of auxiliary airfoils movable relative to the leading edge of the main section and adapted to be positioned to form slots, said auxiliary airfoils being characterized by the fact that profile sections thereof taken'at a plurality of different points in the longitudinal extensions thereof are of different contour, and further characterized by the i'act that means are provided for moving the auxiliary airfoils respectively to a diierent extent relative to the leading edge of the main airfoil section.

8. An airfoil comprising a main airfoil section and a plurality of auxiliary airfoils movable relative to the leading edge of the main section and adapted to be positioned to form a plurality of slots extending successively in a direction from the root to the tiBof the main airfoil section and means for moving the auxiliary airfoils respectively relative to the leading edge of the main airfoil section to position the several auxiliary airfolls respectively at different angles of incidence relative to the main airfoil section.

FRANKR.i/Lllxviuazrlny 

